Variations in the substituted 3-linked mannans closely associated with the silicified walls of diatoms

Abstract

The polysaccharides from cleaned frustules of the diatoms Pinnularia viridis (Nitzsch) Ehrenberg, Craspedostauros australis Cox, Thalassiosira pseudonana Hasle et Heimdal, and Nitzschia navis-varingica Lundholm et Moestrup were extracted with hot alkali that dissolved the silica and were characterized by constituent sugar and linkage analyses. The polysaccharides from P. viridis were investigated further by permethylation, partitioning according to solubility, desulfation, and CD3I-methylation. Yields of carbohydrate in the hot alkali extracts ranged from 0.9% to 1.8% w/w based on the dry weight of the silica. Mannose was the dominant sugar in the polysaccharides from all four species (54-69..